Updated docs.openstack.org page to change wording for API refs intro
Updated docs.openstack.org page to change wording for API refs intro

Change-Id: I1fa9d05a9e1dbac9b1165f379a256f765fa5c367
author: diane fleming

openstack/openstack-manuals,saeki-masaki/openstack-manuals,potsmaster/openstack-manuals,openstack/openstack-manuals,kairoaraujo/openstack-manuals,saeki-masaki/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,Akasurde/openstack-manuals,gongysh2004/openstack-manual,kairoaraujo/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,Akasurde/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,gongysh2004/openstack-manual,potsmaster/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals